Efficiency of Different Nitrogen Fertilizer Sources on Soil Productivity, Fertility and Economically of Wheat Followed by Maize Crops Grown under Calcareous Soil Conditions.

A field experiment was carried out at the farm of Nubaria Agriculture Research Station (Calcareous soil), in two successive winter 2013/2014 & 2014/2015 and summer 2014 & 2015 seasons to evaluate the efficiency of two different sources of nitrogen fertilizers, gas fertilizer ammonia gas 82 %N (AG) and ammonium nitrate 33.5 %N (AN) to enhance soil fertility and get highest economical production of two cereal crops (wheat and maize) grown under calcareous soil conditions. Nitrogen fertilizers doses were 240 kgNha^-1 and 288 N ha^-1 for AG and AN fertilizers compared to zero nitrogen fertilizer rate as control for wheat and maize plants, respectively. The acquired data showed that the injection of ammonia gas fertilizer (82%N) was more efficiency than the ammonium nitrate (33.5%N) for both  wheat and maize crops during two winter and summer seasons. The data revealed that, the average of mean values for two winter and summer seasons of grains weight (g), grains yield, stover yield, biological yield tonha^-1 and relative increasing yield (RIY%) for both wheat and maize plants were superiority by injection ammonia gas (AG) fertilizer compared to control and ammonium nitrate (AN) fertilizer applied. It was noticed that there is a significant difference between the obtained data of harvest index % due to AG injection or AN fertilizer applying during two winter or summer seasons for wheat and maize plants, respectively. On other hand, the mean values of (R.I.Y%) due to AG injection was greater than applying AN fertilizer for wheat and maize plants, respectively. Moreover, the mean values of N, P, K concentration (%), as well as their uptake and protein (%) in grains of wheat and maize plants were a significantly increased by AG injection than AN applying for wheat and maize winter and summer seasons, respectively. From the stand point of nitrogen efficiency, the fertilizing by injection AG fertilizer was more efficiency in terms of productivity factor (P.F) and apparent recovery (AR) compared to AN fertilizer for wheat and maize, respectively. Also, it was noticed that injection AG to  fertilization  wheat and maize crop remarkably positively effect on mean values of N, P and K available than the application of AN fertilizer at harvesting stage, respectively.  Regarding to the farm profitability, the highest net income24691.6 and 13159.8L.E ha^-1 and investment ratio 13.55 and 6.68 were achieved by injection of AG fertilizer for wheat and maize crops as an average of two seasons, respectively. Data also, revealed that the approximate profitably of each added N unit ha^-1 were 102.9 and 45.69L.E with the AG injection for wheat and maize crops respectively, under the experiment conditions.